Temperature-responsive control system



A ril 18, 1939. F. M. cowAN ET AL TEMPERATURE-RESPONSIVE CONTROL SYSTEM Filed Sept. 1'7, 1937 INVENTORS; MCowan, flamers C- Evans,

Frank BY kQA gh ATTORNEY Patented Apr. 18, 1939 PATENT OFFICE TEMPERATURE-RESPONSIVE CONTROL SYSTEM A Frank M. Cowan, Plainfield, N. J. and Francis 0. Evans, Dongan Hills, N. Y., assignors to Ameri- .can District Telegraph Company Inc.', New

York, N. Y., a corporation of New Jersey Application September 1'), 1937, Serial No. 164,286

' 10 Claims. (Cl. 177-455) This invention relates to temperature-responsive alarm or control systems responsive to fire conditions and more particularly to systems of this character which are sufilcie tly sensitive to be afiected by ordinary fluctuations of temperature in the enclosure where the temperature-responsive apparatus is located. a

In certain installations of this character, for example for the protection of rooms or enclosures where unit heaters or blower heater systems are employed, difliculty has been experienced in preventing false alarms because of the rapid rise of temperature produced by this type of heating system in the area adjacent the temperature-responsive apparatus.

Heretofore this difiiculty has been obviatedby decreasing the sensitivity of the temperatureresponsive apparatus, for instance, by increasing the spacing of the electrical contacts in the aerotube system. This reduces the effectiveness of the system to a considerable extent and is therefore undesirable.

it has also been proposed to obviate this dimculty with respect to the production of false alarms by disabling the alarm system for a con-- siderable period or until the general rise in temperature has abated,- such a system being disclosed in the patent to Field No. 976,645, granted November 22, 1910. Such systems are also disadvantageous because of the fact that the alarm system is entirely inoperative for said period and no active protection during suchperiod is provided. It is an object of the present invention to provide neutralizing or compensating means responsive to the unit heater or other normal heating,

source which is associated with the temperatureresponsive systemin such a manner that the fire alarm or control apparatus is substantially unaffected by the temperature changes initiated by the heater or other normal heating source. The compensating device may be arranged to-be unafiected by fire or other abnormal conditions so that full protection is secured against such conditions.

Another object of the invention is to provide compensating means for atemperature-responthe occurrence of fire, irrespective of normal fiuc-' tuations of room temperature oi sufficient magsystem. I

Another object [of the inven tion is to provide nit'ude to operate the temperature-responsive vA further object of the invention is to provide means, in connection witha fire alarm system of the character described, for compensating the response of the system when a unit heater, or heaters, are turned on to an extent corresponding to the heating eflect produced by said heateror heaters.

A'still further object of the invention is to provide ;means, in connection with a fire alarm system having temperature-responsive means, comprising a length of tubing, for controlling the pressure or volume of the air within the tubing upon the occurrence of sudden normal heating changes to compensate therefor without rendering the system unresponsive, at any period, to fire or other abnormal temperature conditions. A'stlll further object of the invention is to provide in a system of the character described,

compensating means in connection with the aero tube system which obviates the formation of a pressure surge upon the air. within the system when the blower heater is turned 01!, or the supply of heat discontinued, thus to prevent a false alarm;

Other objects andadvantages of the invention will appear from the following description of the preferred embodiments thereof shown in the accompanying drawing, wherein Y Fig. 1 is a view, in perspective, of an installation embodying the invention and illustrating the relationship of the compensating device for the fire alarm system and a unit heater for heating the enclosure in which the thernio-sensitive apsection, oi. the compensating device shown in Fig. 1;

Fig. 3 is a cross-section taken on line 3-.-3 oi' Fig. 2, looking in the direction of the arrows:

and I Fig. 4 isan enlarged, fragmentary view, partially insection, of a modification of a compensator.

In accordance with'the present invention, the theme-sensitive ,part of the flre alarm or control system, for example, the pressure tubing of the aero-tube system, is provided with an alarm preventing compensating means in installations where normal sources of heat, such as unit heat-' era, are likely to ailect the response or the fire alarm system and in some cases to cause false alarms. The compensating device is preferably arranged adjacent to the unit heater or other normal sourceof heat and within the heated stream of 'air and is shielded at least to some extent from changes in surrounding atmospheric temperature changes so that it will not be directly aflected by if fire in the enclosure. In the case of the aero-tube system, the compensating unit is arranged to suck sufllcient air from the tubing circuit, preferably at about the center of that part of the tubing circuit affected by the unit heater, to reduce the pressure by an amount equivalent to the atmospheric temperature increase due to the operation of the unit heater.

The operation of the compensating device may be effected by a thermo-responsive element ex posed to the heat from the unit heater whereby the operation of the compensating device corresponds to anydesired entent with the time and magnitude of the temperature change produced by the unit heater. In this manner the pressure developed in the tubing may be precisely countercontacts are operated, as will be described hereinafter.

' order to neutralize or compensate the effect of control system and the operativeness of the system are not aflected, but on the other hand the system is adapted to respond, at all times, under any of its internal conditions to a fire in the enclosure.

It will be evident that this system posseses outstanding advantages over 'prior systemsin which the sensitivity of the fire alarm system was reduced, or in which the system was rendered wholly inoperative during the period when the pressure surge in the tubing was caused by the unit heater or other source.

' which is either partially or completely'hemmed in by walls, floors or other barriers and which may be suitable for or require a fire protection system of the kind to bedescribed' herein. In Fig. 1 this space may include a plurality of connecting rooms and the tubing I may be located at the ceilings of the respective-rooms. The tubing may be arranged and supported in any usual manner and is shown as forming a loop or circuit connected at the ends to a detector unit 2 enclosure resultingfroman actual fire.

The operation of the system is as follows; When the unit heater 3 operates, a relatively rapid rise in room temperature occurs which produces an increase in pressure in the system I just as in the case of the occurrence of a fire. However, the neutralizing unit 4 is connected to the system I, preferably in the middle of the length of tubing which is most affected by the unit heater 3 and is operated by the heat received from the unit heater. The device 4 is arranged, when operated by heat from the heater 3, to suck a volume of air from the tubingl in order to reduce the pressure in the tubing by an amount equivalent to the increase in pressure resulting from the operation of the heater. The operation of the neutralizing orv compensating unit 4 is retarded since it is responsive only to the heating effect oflthe heater 3;

It does not operate at the instant the heater is turned on but may coincide both in time and in effect to the time and magnitude of the pressure surge in the tubing I. It is unnecessary to havean exact neutralization or compensation of the pressure surge in the system, inasmuch as the usual vents in the alarm device 2 will take care of any slight accumulation of pressure in the tubing. Thus it will be seen that by the use of compensating unit 4 not only is the fire detecting system guarded against false alarms but the setting or sensitivity of the system is practically unchanged by the operation of the heater 3 so that the system may be adjusted to maximum sensitivity to fire at all times. From this it is obhaving pressure operated electrical contacts and vents to permit passage of air slowly into or out of the tubing-to compensate for normal variations of temperature such as take place between night and day or seasonalvariations, the vents serving to restrict the air emission and discharge from the tubing sufiiciently so that pressure surges cannot be rapidly released. Thus whenever a fire condition occurs in the enclosure, the

resulting increase in temperature in the'fire area vious thatthe system'is in operative condition at all times, even during compensation periods,

to supervise the protected premises and cause an alarm during fire conditions. The heater 3 is merely illustrative of various sources of heat such as, forges, baking ovens, or furnaces which are able to cause extreme and rapidly changing heat condition.

Furthermore, if there are a number of such sources of heat, a corresponding number of neutralizing units may be provided in the aero tube system to prevent false operation of the alarm system, each neutralizing unit 4 being connected to the portionof the tubing which is affected by said heat source.

There is,.diagrammatically disclosed in Fig.2, a preferred embodiment of a neutralizing or com pensating unit, connected into an aero tube alarm circuit in connection with a blower heater unit which comprises an outer protective casing comprising an enclosing lower shell 6 and an upper heat insulating enclosing shell II superposed on the shell or housing 6 and there held by suitable means, not shown. The shell 6 is provided with an inlet opening 1 which is surrounded by an open-ended funnel member which is located adjacent the'heat emission or .discharge opening in the heater unit 3, shownin Fig. 1, thereby to receive and direct some of the heated stream from the blower heater into the. interior of the shell 6, as indicated by the ar-. rows 2|, which stream passes out at the apertures 32 at the rear thereof. I

The casing 6-H is divided into two chambers,

' vertically as viewed in Fig. 2, by a heat insulat located a sylphon bellowsi which is provided with a small vent 3|. At the bottom thereof is attached a collar 23 to which is suitably pinned upper bellows 9. The aero tubing, as seen in.

an interiorly mounted-vertical shaft 8 which is connected at its opposite, upper end to the lower end of a second sylphon bellows 9 which is thermally insulated and is mounted in the upper shell I l. The upper sylphon bellows 9 also sealed and is firmly attached atits upper end to the underface of a support plate 24 which in turn is supported on four corner posts 25, Figs. 2 and 3,

which are fixedly mounted in ba'flle plate l2.

As thus described, when heat strikes lower bellows 5,. it expands and this action expands the Fig.2, has its ends connectedinto the support plate through shell H and is thus connected into the interior of the sealed. bellows 9. Thus, when bellows 5 expands through the'agencyof.

' heat from the blower heater unit 3, it draws 4o bellows 9 downwardly by means ofcthe shaft 8 which passes through an aperture 21 in the support plate i2 and upon suchdownward action of being located within the shell 6 adjacent the collar 23, the stem 28 extending exteriorly of the bottom of shell 6 which is bored therefor.

Shell 6 at the bored portion is provided'with an aflixed threaded nut 29 with which stem 28 engages, and a lock nut 39 engages on said stem 28 and is jammed against=nut 29 to lock the plug in any adjusted position in which it may be set to control the expansion action of the bellows 5: to, any desired degree. In adjusting 'the plug it, the nut 39 is loosened and a screw driver is entered in the slot of stem 28, Fig. 2,

- flanged edge of the rectangularlycomformed and the stem is then rotated for position and again locked by nut 30.

As a means for preventing the belows 9 from suddenly collapsing and creating an alarm ini- -tiating pressure surge in the ,aero tube circuit l'after prolonged actuation of the heater unit 3, the be ows 9 at its point of connectionto shaft 9 is provided with a bimetallic thermostatic metal strip l3 which is firmly connected thereto, Figs. 2 and 3. The ends of the strip l3 are downwardly bent, Fig. 2, and engage under the upper This extraction of airfrom the,

flanged holder I4 which is suitably afllxed to the upper face of the baiiie plate I 2, Figs. 2 and 3,

and frames the aperture 21, Fig. 3.

When the heat from the unit 3 is of prolonged duration and is suddenly stopped, the strip it,

which has become heated through aperture 21, is straightened out slightly and locks bellows 9 in expanded position. As this apparatus slowly cools, the strip l3 gradually assumes its normal position and gradually returns the extracted air into; the aero tube system, thus restoring normal conditions'therein. As the tube system and bellows are gradually restored to normal, air is slowly readmitted into the bellows 5, from -at mosphere, through the vent 3| therein.

The aero tube circuit and alarm means, shown in Fig. 2 more or 'less diagrammatically and in partial section, are of a well known type and will now be briefly described.

The two opposite ends of the aero tube system I are each connected to one of the two connections 36 and 3'! of an alarm device, generally denoted by'2, Fig. 2, at 34 and 36.

The alarm device 2 comprises two separate, chambered members 36 and 31. The upper opposite portions ofthemembers 36 and 31 are provided with the usual atmospheric vents 4242, whereby normal breathing of the air in the aero system is permitted to normally vary under nor-- mal atmospheric temperature changes.

The members 36 and 31 are provided with open ended tubular extensions 48 and 49, respectively, and the open ends are each closed by a double expansion diaphragm 38 and 39. These diaphragms are provided at their outer faces with electrical contacts 46 and 41. Opposite to the contacts 46 and 41 and-adjustably spaced therefrom are suitably supported adjustable contact screws 49 and 4 I. When a flre initiated surge takes place in the system the diaphragms expand, thus to close with contact points 40 and 4| and thereby close and operate the "electrical alarm circuit, now to be described. r The electrical alarm circuit comprises an electrical current source 44, Fig. 2, and an audible the same indices as shown in Figs. 1, 2 and 3.

Only fragments of the coacting parts are shown. This embodiment comprises a housing 6--l I, the baflle support l2 located on flange 22 therein, the support uprights 25, the inlet funnel 29 at the aperture I and the heaterunit 3.

The baffie l2 has an aperture therein in which (I is mounted a 'reciprocatory stud 8' which is prof vided with spaced shoulders l6 and IS on opposite ends thereof, one end, l6, being locateddn the chamber of shell 6, the other shoulder l6 at one of its ends, the free offset end thereof being operatively connected to the upper surface of the shoulder I6.

The upper-end of lug II is firmly attached to a cylphon bellows l which is located above the stud 8' and is operatively mounted and functions as described for upper bellows 9, of Fig. 2.

In operation, in conjunction with a heated air stream passing through the lower chamber 6, and as shown by the arrows 2l-33, from the heater unit 3, the strip ii tends to draw the stud 8' and with it the attached upper bellows and this action extracts airfrom the aero system I, as described for Figs. 1 and 2. This ac tion also stresses the spring i3 downwardly.

When the blower heater unit .3 ceases operation, the strip [5 gradually becomes cooler and under the uplift action of spring IS, the extraction sylphon gradually restores the air back into the aero tube system without surging.

The blower heater system herein briefly de- 4 scribed in its standard embodiment, is provided with thermostatic-controls which, when the atmospheric temperatures drop, initiate the operation of the heater until predetermined temperai tures are reached, whereupon the thermostat ceases operation. The thermostatic controls are well known and are not herein shown but are understood.

From the foregoing it will be noted that the neutralizing or compensating means acts as a full time monitor for the aero-tube system and enclosure said monitoring control supervising the that it controls the air pressures in said system against all tendency to initiate any alarms except alarm conditions set up by a'tlre within the aero-tube system under and during any and all air conditions within the tube, including conditions of sudden surge in the aero-tube due to fire conditions. It also monitors the aero-tube system during a drop in pressure-within said tube system to prevent vacuum surges therein and this is all accomplished without any disablernent of the constant supervisory alarm initiating means.

It will be obvious from the foregoing that modi-' iicationsqnay be made in the structure herein dissive means when the heating means is turned on "and ofl, and compensating means associated with said temperature-responsive means and arranged to be aflected by said heating means in a manner to counterbalance the response of said temperature-responsive means, to substantially eliminate the effect of the heating means thereon, upon a rise in temperature in the enclosure from the operation of the heating means.

2. In combination, an enclosure, temperature.- r'esponsive means arranged to supervise the temperature changes in said enclosure and to operate upon the occurrence of apredetermined rise in temperature therein, means responsive to said temperature responsive means and compensating means associatedwith said temperature responsive means and arranged to be affected by normal temperature changes in the enclosure to counterbalance the response of the temperature-responsive means, during changes in temperature which may be expected in point of intensity but unexpected in point of time, whereby the latter will operate substantially uniformly at all times'on responsive means including an aero-tube system arranged to supervise temperature changes in said enclosure and to operate upon apredetermined increase in the pressure in said aero-tube system means responsive to said temperature responsive means and a compensating pressure controlling device connected/to said aero-tube systemand arranged to-be aflected by normalheating conditions in the enclosure whereby the pressure changes in the aero-tube system are substantially unafiected by such conditions.

4. In combination, an enclosure, heating means for said enclosure, temperature-responsive means including an aero-tube and alarm system arranged to supervise fluctuating temperature changes in said enclosure and system and to operate said alarm upon a predetermined increase in pressure in said aero-tube system and compensating means connected to said aero-tube system arranged to decrease pressure variations therein resulting from temperature changes caused by said heating means, said last-named means. comprising means to extract air from the aero-tube system operated by heat from said heating means, and means to gradually restore air to said aero-tube systemto. its normal atmospheric pressures, when the heating means is turned on.

5., In combination with an aero-tube alarm system, a blower heater adjacent to said system com,- prising a casing, said casing having inlet and outlet apertures therein, a thermo-sensitive means in said casing in line with said apertures adapted to change its condition when heat from the blower heater is passed through said apertures and air extractive means connected to said aero-tube system and operable by said thermo-sensitive means whereby when the latter changes its con-' dition, the extractive means gradually extracts air from said aero-tube system.

6. In combination with an aero tube alarm system, a blower heater adjacent to said system comprising a casing, said casing having inlet and outlet apertures therein, a thermo-sensitive means in said casing in line with said apertures adapted to change its condition, when heat from the blower heater is passed through said apertures, air extractive means connected to said aero-tube system and operable'by said thermosensitive means whereby when thelatter changes its condition the extractive means gradually extracts air from said aero-tube system and a sec- 0nd thermo-sensitive means associated with said first thermo-sensitive and said airextractive tive means in said casing in line with said apertures adapted to change its condition, when heat apertures, or turned 01! and air controlling means connected to said aero-tube system and operable from the blower heater is passed through said by said thermo-sensitive means whereby when the latter changes its condition the air controlling means gradually extracts or restoresair from or to said aero-tube system.

I 8. In combination, temperature-responsive means arranged to supervise atmospheric temperature changes and to operate upon the occurrence of a predetermined change in atmospheric temperature, atmospheric heating means afiecting the temperature-responsive means when the heating means is turned 'on and off and compensating means associated with said temperature-responsive means and arranged to be affected by said heating means in a manner to counterbalance the response of saidtemperatureresponsivemeans, to modifypthe effect of the heating means thereon, upon a rise in temperature in the atmosphere caused by the operation of the heating means.

9. In combination, an enclosure, temperature responsive means arranged to supervise temperature changes in said enclosure, heating means capable of causing response by said temperature responsive means, means responsive at all times to said temperature responsive means upon the occurrence of temperature variations resulting from fire conditions or other abnormal conditions and compensating means for preventing response by said means responsive to said temperature responsive means during temperature changes resulting from the action of said heating means.

10. In combination, an enclosure, heating means therein, temperature responsive means having a portion thereof directly exposed to said heating means and arranged to supervise temperature changes in said enclosure, means responsive to said temperature responsive means during all changes of temperature resulting from fire conditions or other abnormal conditions and compensating means associated with said temperature responsive means for preventing operation of said means responsive to said temperature responsive means during all normal changes of temperature.

- FRANK M. COWAN.

FRANCIS C. EVANS. 

